1. Field of the Invention
The present invention relates to an apparatus for heating or cooling a circular housing.
2. Discussion of the Background
The housings of turbo-machines are cooled or heated, as appropriate, by standard means that adjust their diameter by dilating or contracting them under the influence of heat. It is therefore possible to accurately adjust the play between the housing and the rotor that it covers, especially at the ends of the rotating blades of the rotor, in order to reduce gas leakage which escapes through the play and reduces the machine's efficiency. Another advantage of this arrangement, which only exists however when using cold gas, is that it avoids overheating the housing and the apparatus that it supports or that are adjacent to it. In any event, the gas is taken under pressure from another area of the machine and is blown onto the outer surface of the housing at a rate that can be constant or monitored according to the speed of the motor. In some designs the gas is blown directly onto the outer surface of the housing. In other configurations, such as French patent 2 688 539 filed by the same applicant, the housing is stiffened by circular ribs on the outer surface and the gas is blown mainly onto these ribs, although some gas can also be blown directly onto the housing. Blowing on the ribs is advantageous as it uses a larger thermal exchange surface area, thereby quickening thermal distortion of the housing.